方法：BALB/c小鼠60只随机分为实验组A、实验B及对照组C，每组20只。采用1mol/L氢氧化钠溶液烧伤小鼠右眼角膜，建立炎症性角膜碱烧伤动物模型，分别予以A组、B组重组Canstatin蛋白3μg/mL、5μg/mL点右眼，4次/d，对照组C组予以生理眼水点右眼。在碱烧伤后第1、3、7、14d以形态学分析评价角膜上皮损伤面积及新生血管生长的情况，并于碱烧伤后第1、3、7、14d应用Western-blot检测角膜MMP-2和TIMP-2的表达，增强化学发光法(ECL)对结果进行分析。

结果：形态学分析显示，A组和B组小鼠在碱烧伤后第3d起各时间点角膜上皮缺损面积均小于对照组(P<0.01)，角膜新生血管均得到抑制，CNV面积明显小于对照组(P<0.01)。Western-blot结果显示，碱烧伤后各时间点MMP-2的表达，A组和B组均明显低于对照组(P<0.01)，TIMP-2的表达高于对照组(P<0.01)，且A组和B组间MMP-2的表达在第14d比较差异有统计学意义(P<0.05)，TIMP-2的表达在第7d及第14d比较差异有统计学意义(P<0.05)。

结论：重组Canstatin蛋白可通过抑制角膜细胞及浸润的炎性细胞产生MMP-2，促进TIMP-2表达，从而抑制和延迟碱烧伤后角膜融解的发生和发展，对碱烧伤后角膜的重塑起着重要作用。

METHODS: Sixty BALB/c mice were divided into three groups(experimental group A, experimental group B and control group C), 20 mice in every group and their corneas in the right eyes were burned with alkali(1mol/L NaOH). The experimental group A received recombinant canstatin proteins drops with 3μg/mL. The experimental group B received recombinant canstatin proteins drops with 5μg/mL and the control group C was treated with physiologic saline. At different time points(1, 3, 7 and 14 d)after alkali burns, the mice were killed and the growth of epithelial defect and corneal neovascularization(CNV)were observed with an operation microscope. The expressions of MMP-2 and TIMP-2 in cornea were measured by the Western blot technique, and the results were analyzed by enhanced chemiluminescent(ECL).

RESULTS: The areas of epithelial defect and corneal neovasularization significantly reduced in mice treated with recombinant canstatin proteins compared to mice treated with physiologic saline at 3, 7 and 14d after alkali-induced injury( all P<0.01); the neovasularization was suppressed and the area of CNV was less than that in control group C(all P<0.01). Western blot analysis showed that the expression levels of MMP-2 in experimental group A and B were significantly lower than that in control group C(P<0.01)and the expressions of TIMP-2 in experimental group A and B were significantly higher(P<0.01); the level of MMP-2 in experimental group B were lower than that in experimental group A on day 14(P<0.05), while the level of TIMP-2 in experimental group B were significantly higher than that in experimental group A on day 7 and day 14(P<0.05).

CONCLUSION: Recombinant canstatin proteins may suppress the expression of MMP-2, upregulate the expression of TIMP-2 in cornea cells and the infiltrated inflammatory cells, lower the rapid resolution of cornea and ulceration, and play a vital role in the remodeling of alkali treated cornea in mice.